Such an axle is known from U.S. Pat. No. 6,588,778 B1. It is designed as a carrying axle for a trailer and has an axle body, an axle spring mounting and a rocker arm assembly. The rocker arm assembly has a one-piece design and consists of an inner axle tube and a rocker arm, which have different cross-sectional shapes and which are produced from a premanufactured one-piece tube by a hydroforming process. The inner axle tube plugs in an outer axle tube, which is connected to the trailer, whereby elastic cords are inserted between them for forming the axle spring mounting. An axle stub is inserted at the free end of the tube of the rocker arm, which is bent several times. The prior-art rocker arm assembly requires a high and costly construction effort.
FR 2 753 930 shows a similar rubber spring axle with a one-piece rocker arm assembly that consists of a premanufactured and bent tube with a circular cross section. This construction also has a high and costly construction effort, whereby the bending of premanufactured tubes with a closed jacket may also cause difficulties with the accuracy to size and strength.